Process of cracking petroleum oil



` Jul; *31, 1928.

A 5. EGLOFF PROCESS OF CRACKING PETROLEUM OIL Filed 001'.. 22, 1925 difk' A l I Patented July 31, 192s.

UNITED STATES PATIENT` OFFICE.

i GUSTAV EGLOFF, OF CHICAGO, ILLINOIS, ASSIGNOR T UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA.

PROCESS OF CRACKING PETROLEUM OIL.

Application led October 22, 1923. Serial No. 669.931.

This invention relates to improvements in process of cracking petroleum oil, and refers more particularly to that type of cracking process in which the oil is passed first through a heating coil and thence to an expansion chamber; the vapors removed therefrom and subjected to reux condensing action. In this type of process it is desirable to keep the tubes as free as possible from carbon and to accomplish this it is desirable to avoid returning the residuum to the heating coil, inasmuch as the residuum contains the maximum amount of carbon. At the same time residuum is not always completely converted, and it is often desirable to subject the residuum to further cracking conditions of temperature and pressure. I

The object of the invention is for the purpose of accomplishing this without stopping up the heating coil and without substantially modifying the present type of apparatus. i

The invention will be understood from the following description, reference being had to the accompanying drawing, in which the single figure represents a somewhat diagrammatic side elevation and vertical section Vof an apparatus suitable for carrying out the invention.

Referring to the drawings (1) designates a furnace, in which is mounted'heating coil (2) which may take the form of a `con tinuous coil. Raw oil is fed to this coil by the pump.(3) through feed line (4) and the heated oil is delivered fromthe coil to the upper end of expansion chamber (5) by means of transfer line (6) having throttle valve (7). Expansion chamber (5) may take the form of vertically extending cylinder (8). The vapors pass out of the upper chamber (5) through line (9) controlled by valve (10) to the dephlegmator (11). 'This dephlegmator l(11) has at its upper end va or outlet pipe 12 controlled by valve 13 an leading to coil (14) set in condenser box (15). The oil passes out of the condenser coil into the upper end of receiver (16) which -latter has gas control valve (17) and liquid control valve (18.).

The reiux condensate may be returned directly to the heatinor coil by means of the ipe (19), controlled by valve (20), leading ack to feed pipe (4). The resi( uum may be drawn off from the lower end of the expansion chamber through pipe (21) having control valve (22). The residuum then may pass through line (23) having control valve (21) to circulating pump (Q5) and thence through pipe (26) having valve (27) to the transfer line (6) at a point adjacent where it enters the expansion chamber as shown at (28). Certain of the residuum may be evacuated from the system, if desired, through branch (29)'having control valve As a feature of the invention the uncondensable gas is mixed with the residuum in the line (26) before the residuum is returned to the expansion chamber. This is accomplished by means of gas pump (31) and pipe (3.2) connected to the upper end of the receiver and to the line. (26) respectively; a siotible valve (33) being interposed in line 'l` he uncondensable gas is mixed with the residuum in such proportions as to more or less atomize the residuum and thus get a more effective heat transfer between the hot oil from lthe transfer line (6) and the residuum, and thus produce more effective recracking of the residuum.

By means of the present invention practically all of the oil can be recracked, and 1n most cases it will not be necessary to withdraw any residue through line (Q9) but only to clean the coke outof the reaction chamber. This will result, of course, in producing the maximum amount of given oil from the cracking crude and avoid accumulation of liquid residue. The process may be opera-ted at pressures from 100 to several hundreds of pounds or more. and the oil heated to a. temperature of 850 F. more or less as it leaves the transfer line.

I claim as my inventionf 1. A continuous process of oil conversion comprising advancing a stream of oil through a heating zone wherein it is raised to a cracking temperature, introducing highly heated oil into an enlarged reaction lzone wherein a body of oil accumulates and substantial vaporization takes place, dephlegmating the evolved vapors, cont-inuously withdrawing unvaporized residual oil from said reaction zone below the liquid level of the oil therein. introducing to the unvaporized residual oil a portion of the uncondensable gases produced in the process, returning such withdrawn residual oil to-- gether with the uncondensable gases introduced thereto under pressure direct-ly and Without passage through said heating zone into the vapor space of said reaction zone to undergo further treatment therein, and maintaining a superatmospheric vapor pres sure on the oil in said stream and in said reaction zone.

2,; A continuous process of oil conversion comprising subjecting an advancing stream of oil to a cracking temperature in a heating lzone, passing heated oil from said stream into an enlarged reaction chamber wherein a body of liquid oil accumulates and substantial vaporization occurs, dephlegmating the evolved vapors, continuously Withdrawing unvaporized residual oil from said reaction zone, isolating predetermined portions of such vresidual oil from the system, uniting with the remaining portions of the residual oil uncondensable gases produced in the process, returning such portion of the unvaporized oil and the uncondensable gases united therewith directly and Without passage through said heating zone to the vapor space of said reaction chamber for further treatment.

GUSTAV EGLOFF. 

